Ceftolozane-tazobactam pharmaceutical compositions

ABSTRACT

Pharmaceutical compositions are provided in unit dosage forms comprising ceftolozane and tazobactam in separate unit dosage form containers, ceftolozane prepared in the absence of tazobactam, tazobactam prepared in the absence of ceftolozane, and/or compositions where ceftolozane and tazobactam are first combined within a unit dosage form container.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application No. 61/792,092, filed Mar. 15, 2013, and U.S. Provisional Patent Application No. 61/793,007, filed Mar. 15, 2013, both of which are incorporated herein in their entirety.

TECHNICAL FIELD

This disclosure relates to antibacterial compositions comprising ceftolozane and tazobactam.

BACKGROUND

The pharmaceutical antibiotic composition comprising ceftolozane and tazobactam in a 2:1 weight ratio of ceftolozane active to tazobactam acid (“CXA-201”) displays potent antibacterial activity, including antibiotic activity against infections caused by many Gram-negative pathogens such as Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli), Klebsiella pneumonia (K. pneumonia). In particular, CXA-201 is a pharmaceutical composition being developed for intravenous administration for the treatment of complicated intra-abdominal infections and/or complicated urinary tract infections, and is being evaluated for treatment of pneumonia.

Ceftolozane is a cephalosporin antibacterial agent, also referred to as CXA-101, FR264205, or by chemical names such as (6R,7R)-3-[(5-amino-4-{[(2-aminoethyl)carbamoyl]amino}-1-methyl-1H-pyrazol-2-ium-2-yl)methyl]-7-({(2Z)-2-(5-amino-1,2,4-thiadiazol-3-yl)-2-[(1-carboxy-1-methylethoxy)imino]acetyl}amino)-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate, and 7β-[(Z)-2-(5-amino-1,2,4-thiadiazol-3-yl)-2-(1-carboxy-1-methylethoxyimino)acetamido]-3-{3-amino-4-[3-(2-aminoethyl)ureido]-2-methyl-1-pyrazolio}methyl-3-cephem-4-carboxylate. The antibacterial activity of ceftolozane is believed to result from its interaction with penicillin binding proteins (PBPs) to inhibit the biosynthesis of the bacterial cell wall which acts to stop bacterial replication. Ceftolozane sulfate is a pharmaceutically acceptable ceftolozane salt of formula (I) that can be formulated for intravenous administration or infusion.

In CXA-201, ceftolozane is combined with the β-lactamase inhibitor (“BLI”) tazobactam. Tazobactam is a BLI against Class A and some Class C β-lactamases, with well-established in vitro and in vivo efficacy in combination with active β-lactam antibiotics. Tazobactam can be combined with ceftolozane as a lyophilized composition obtained by lyophilizing a solution of water, a sodium containing base (e.g., sodium bicarbonate) and the tazobactam acid form of formula (II).

Pharmaceutical compositions comprising one or more drug substances can be prepared by lyophilization of a solution containing the drug substance(s). Lyophilization is a process of freeze-drying in which water is sublimed from a frozen solution of one or more solutes. Specific methods of lyophilization are described in Remington's Pharmaceutical Sciences, Chapter 84, page 1565, Eighteenth Edition, A. R. Gennaro, (Mack Publishing Co., Easton, Pa., 1990). The formulation of pharmaceutical compositions can be selected to minimize decomposition of the constituent drug substances and to produce a composition that is stable under a variety of storage conditions.

As disclosed herein, compositions formed by lyophilizing ceftolozane and tazobactam demonstrated an increase in total ceftolozane related substance impurities over time of about 31-36% after 3 months at 25 degrees C. (e.g., see data tables in FIGS. 6A and 9A) and about 200-264% after 3 months at 40 degrees C. (e.g., see data tables in FIGS. 6B and 9B). As a result of increasing ceftolozane related substance impurities over time, the amount of ceftolozane in a pharmaceutical composition can decrease prior to placement of a ceftolozane composition within a unit dosage form container. Unit dosage forms that fail to comply with applicable specifications over time, such as the ceftolozane purity or increased amounts of ceftolozane related substances over time, cannot be used to treat patients and must be safely and appropriately discarded. This points to a potential benefit of unit dosage forms of pharmaceutical compositions (e.g., CXA-201 compositions) with reduced levels of ceftolozane related substance impurities for longer periods of time after manufacturing, and methods of manufacturing these unit dosage forms (e.g., to extend the shelf-life of the unit dosage form product).

SUMMARY

Pharmaceutical compositions comprising ceftolozane and tazobactam can be manufactured to reduce the total amount and/or the rate of formation of certain related substances present in the pharmaceutical compositions over time by first combining the ceftolozane and tazobactam within a unit dosage form container (e.g., a vial, bag or other container) in powder form for later reconstitution (“split-fill” presentation), or by providing ceftolozane and tazobactam in separate containers for combination in a fixed dose ratio at a point of patient treatment (“two-container” presentation). In both presentations, the point of first contact of a ceftolozane-containing composition with a tazobactam-containing composition is closer in time to subsequent patient administration than in the products manufactured by processes that combine ceftolozane and tazobactam in a single (e.g., blended) composition prior to filling of the composition(s) into a unit dosage form container. As a result, the time available for formation of ceftolozane related substance impurities within the product is reduced in the products disclosed herein.

The unit dosage form containers can be obtained by a “split-fill” process comprising the steps of: (a) sequential, aseptic filling of the ceftolozane and tazobactam into a unit dosage form container; (b) blanketing the unit dosage form container with an inert gas; and (c) sealing the unit dosage form container.

Alternatively, a product presentation comprising separate unit dosage form containers can be obtained by a “two-container” process comprising the steps of: (a) aseptic filling and sealing of a ceftolozane composition in a first unit dosage form into a first container in the absence of tazobactam; (b) aseptic filling and sealing of a tazobactam composition in a first unit dosage form into a second container in the absence of ceftolozane; and (c) packaging the first container and the second container as a single product for later combination in a fixed dose combination of the ceftolozane composition and the tazobactam composition in a weight ratio of 2:1 between the amount of ceftolozane active and tazobactam free acid. The two-container product presentation can also be obtained by a process comprising the steps of: (a) providing a ceftolozane composition prepared in the absence of tazobactam, (b) providing a tazobactam composition prepared in the absence of ceftolozane, (c) aseptic filling and sealing of the ceftolozane composition in a first unit dosage form into a first container; (d) aseptic filling and sealing of the tazobactam composition in a second unit dosage form into a second container in the absence of ceftolozane; and (c) packaging the first container and the second container as a single product for later combination in a fixed dose combination of the ceftolozane composition and the tazobactam composition in a weight ratio of 2:1 between the amount of ceftolozane active and tazobactam free acid.

Measurements of ceftolozane related substances can be identified as compositions having the retention times for peaks 1-11 in Table 1, as identified by high performance liquid chromatography (HPLC), where HPLC measurements are made using a Develosil column ODS-UG-5; 5 micrometers; 250×4.6 mm, a mobile phase of sodium perchlorate buffer solution (pH 2.5)/CH₃CN 90:10 (v/v) at a 1.0 mL/min flow rate and oven temperature of 45° C. (i.e., as used herein, “related substances”).

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are chromatograms of CXA-101 ceftolozane drug substance obtained from the lyophilization process of Example 1. The chromatograms were obtained according to the analytical method described in Example 2.

FIG. 2 is a diagram of a lyophilization process for the ceftolozane obtained according to the process described in Example 1.

FIG. 3 is a table (Table 1) of peaks for the ceftolozane prepared by the lyophilization process in Example 1 obtained by HPLC according to the analytical method of Example 2.

FIG. 4A is a schematic showing a process for making a Co-Lyophilized Composition with ceftolozane and tazobactam.

FIG. 4B is a table (Table 2) showing a first composition that can be lyophilized to form a Co-Lyophilized Composition.

FIG. 5 is a table (Table 3) showing a second composition that can be lyophilized to form a Co-Lyophilized Composition.

FIG. 6A is a table (Table 4) showing the amount of various materials identified in Co-Lyophilized Composition of FIG. 5, comprising the related substances at a first temperature (25 degrees C.) as measured by HPLC peak area according to the analytical method of described in Example 2.

FIG. 6B is a table (Table 5) showing the amount of various materials identified in Co-Lyophilized Composition of FIG. 5, at a second temperature (40 degrees C.) as measured by HPLC peak area according to the analytical method of described in Example 2.

FIG. 7 is a table (Table 6) showing in-process testing of blending a composition comprising ceftolozane and tazobactam at three places.

FIG. 8 is a table (Table 7) showing a blended composition comprising ceftolozane and tazobactam.

FIG. 9A is a table (Table 8) showing the amount of various materials identified in a second blended composition of FIG. 7, comprising the Related Substances at a first temperature (25 degrees C.) as measured by HPLC peak area according to the analytical method of described in Example 2.

FIG. 9B is a table (Table 9) showing the amount of various materials identified in a second blended composition of FIG. 8, at a second temperature (40 degrees C.) as measured by HPLC peak area according to the analytical method of described in Example 2.

DETAILED DESCRIPTION

Pharmaceutical compositions comprising ceftolozane (e.g., ceftolozane sulfate) and tazobactam (e.g., tazobactam sodium) can be obtained by processes that reduce the total amount of related substances after the compositions are placed in a unit dosage form container and prior to opening these containers for administration of the product to a patient. The products can be manufactured by methods that avoid contact of ceftolozane and tazobactam prior to placement in a unit dosage form container or prior to formulation of a fixed dose ceftolozane-tazobactam combination product from multiple product containers.

Preferably, products disclosed herein provide less time for formation of ceftolozane Related Substances within the unit dosage form container than alternative product presentations where ceftolozane and tazobactam are brought into contact prior to placement in one or more unit dosage form containers. As used herein, the term “related substances” refers to compositions having the characteristic retention times for peaks 1-11 in Table 1 identified by high performance liquid chromatography (HPLC), where the HPLC measurements are made using a Develosil column ODS-UG-5; 5 micrometers; 250×4.6 mm, a mobile phase of sodium perchlorate buffer solution (pH 2.5)/CH₃CN 90:10 (v/v) at a 1.0 mL/min flow rate and oven temperature of 45° C. Tables 5-6 and 8-9 provide the amounts of Related Substances observed in various samples during certain stability testing. FIGS. 1A and 1B are chromatograms of CXA-101 ceftolozane drug substance obtained from the lyophilization process of Example 1. The chromatograms were obtained according to the analytical method described in Example 2. FIG. 3 is a table of peaks for the ceftolozane prepared by the lyophilization process in Example 1 obtained by HPLC according to the analytical method of Example 2. The unit dosage forms manufactured according to preferred embodiments disclosed herein provide compositions comprising ceftolozane and tazobactam having a total amount of related substances that is less than the drug product specification shown in FIG. 9A under drug product specification (i.e., less than about 7% by HPLC performed by the method of Example 2). More preferably, the total related substances in the unit dosage forms comprising ceftolozane and tazobactam is less than about 2.5% (e.g., about 1.5% or less for t0 measurement in FIG. 6A or about 2% or less for t0 measurements shown in FIG. 9A).

FIG. 8 is a table of an example of a blended composition of ceftolozane and tazobactam that was tested to obtain the data in the tables of FIGS. 9A and 9B. Referring to the data tables in FIGS. 9A and 9B, the amount of related substances in blend compositions were determined by HPLC as described in Example 2, in two different stability tests. The data in the table of FIG. 9A was obtained from a 3 month stability study where the co-lyophilized composition of FIG. 8 was maintained at 25 degrees C. and 60% relative humidity (RH) for 1 and 3 months. The data in the table of FIG. 9B was obtained from a 3 month stability study where the co-lyophilized composition of FIG. 5 was maintained at 40 degrees C. and 60% relative humidity (RH) for 1 and 3 months. The product presentations described herein are based in part on the discovery that compositions prepared by blending separate ceftolozane and tazobactam compositions (e.g., Example 5 and FIGS. 8, 9A and 9B) showed slower rates of formation of the Related Substances than co-lyophilized compositions (e.g., of Example 3 and FIGS. 5, 6A and 6B) during 3 month stability testing, even though the initial amounts of the Related Substances were lower in the co-lyophilized compositions in comparison with those present in the blend compositions.

For example, a composition formed by lyophilizing ceftolozane and tazobactam separately and then blending these components listed in FIG. 8 demonstrated an increase in total ceftolozane related substance impurities (peaks 1-11) measured by HPLC (Example 2) over three months at 25 degrees C. and 60% relative humidity (from T0 to T2 in FIG. 9A) from about 2.0% (i.e., the sum of peaks 1-11 in the t0 column of Table 8, counting “<0.03%” as 0) to about 2.7% (i.e., the sum of peaks 1-11 in the t2 column of Table 8, counting “<0.03%” as 0), corresponding to an increase of about 31% in related substances over three months at 25 degrees C. and 60% relative humidity. A composition formed by lyophilizing ceftolozane and tazobactam separately and then blending these components listed in FIG. 8 demonstrated an increase in total ceftolozane related substance impurities (peaks 1-11) measured by HPLC (Example 2) over three months at 40 degrees C. and 75% relative humidity (from T0 to T2 in FIG. 9B) from about 2% (i.e., the sum of peaks 1-11 in the t0 column of Table 9, counting “<0.03%” as 0) to about 4% (i.e., the sum of peaks 1-11 in the t2 column of Table 9, counting “<0.03%” as 0), corresponding to an increase of about 200% in Related Substances over three months at 40 degrees C. and 75% relative humidity.

A composition formed by co-lyophilizing ceftolozane and tazobactam listed in FIG. 5 demonstrated an increase in total ceftolozane related substance impurities (peaks 1-11) measured by HPLC (Example 2) over three months at 25 degrees C. and 60% relative humidity (from T0 to T2 in FIG. 6A) from about 1.5% (i.e., the sum of peaks 1-11 in the t0 column of Table 4, counting “<0.03%” as 0) to about 2% (i.e., the sum of peaks 1-11 in the t2 column of Table 4, counting “<0.03%” as 0), corresponding to an increase of about 36% in related substances over three months at 25 degrees C. and 60% relative humidity. Similarly, the composition formed by co-lyophilizing ceftolozane and tazobactam as listed in FIG. 5 demonstrated an increase in total ceftolozane related substance impurities over time from about 1.5% related substances at t0 in Table 5 to about 3.9% in Table 5 (corresponding to an increase of 1.5% to 3.9%, or about a 264% increase in related substances over three months at 40 degrees C. and 75% relative humidity).

The rate of increase in related substances for peaks 1-11 was greater in the co-lyophlized ceftolozane-tazobactam sample of Table 3/FIG. 5 than the blended ceftolozane/tazobactam sample of Table 7/FIG. 8 in both 3 month stability tests. The first test was conducted at 25 degrees C. and 60% RH. The blended ceftolozane-tazobactam sample of Table 7/FIG. 8 also showed an increase in related substances of about 31% after 3 months at 40 degrees C., compared to an increase of about 36% for a co-lyophilized composition described in Table 3/FIG. 5 after 3 months at 40 degrees C. under comparable stability testing conditions. The second stability test was performed for 3 months at 40 degrees C. and 75% relative humidity. The blended ceftolozane-tazobactam sample of Table 7/FIG. 8 showed an increase in Related Substances of about 200% after 3 months at 40 degrees C., compared to an increase of about 264% for a co-lyophilized composition described in Table 3/FIG. 5 under comparable stability testing conditions.

Pharmaceutical compositions comprising ceftolozane and tazobactam can be manufactured and formulated to reduce the total amount and/or the rate of formation of certain related substances present in the pharmaceutical compositions over time. In particular, ceftolozane-containing compositions can be manufactured and handled in the absence of contact with tazobactam prior to enclosure within a unit dosage form container, for example by lyophilization of a composition comprising ceftolozane sulfate and a stabilizing agent such as sodium chloride (e.g., 125 mg-500 mg of sodium chloride per 1,000 mg of ceftolozane active equivalent). Tazobactam-containing compositions can be manufactured and handled in the absence of contact with ceftolozane prior to enclosure within a unit dosage form container. Preferably, the compositions are obtained by a process comprising the step of first contacting ceftolozane and tazobactam within a unit dosage form container (e.g., a vial), thereby extending the shelf life of the product in comparison to compositions where tazobactam and ceftolozane are first contacted in a blend outside of the unit dosage form container and subsequently transferred to the unit dosage form container.

The pharmaceutical compositions comprising ceftolozane and tazobactam can be prepared by a process wherein the ceftozolane and tazobactam are individually lyophilized in the absence of one another, followed by aseptically combining the individually lyophilized ceftozolane and tazobactam within a unit dosage form container. Alternatively, the pharmaceutical compositions comprising ceftolozane and tazobactam can be prepared by a co-filling process, wherein the ceftozolane and tazobactam are individually lyophilized in the absence of one another, followed by co-filling the individually lyophilized ceftozolane and tazobactam in a vial. In an embodiment of the co-filling method, ceftolozane and tazobactam are sequentially administered into a vial. Specific methods of lyophilization are described in Example 1 and Remington's Pharmaceutical Sciences, Chapter 84, page 1565, Eighteenth Edition, A. R. Gennaro, (Mack Publishing Co., Easton, Pa., 1990). FIG. 2 is a diagram of a lyophilization process for the ceftolozane obtained according to the process described in Example 1.

The products include a ceftolozane composition prepared and handled in the absence of tazobactam by forming a first aqueous solution comprising ceftolozane sulfate and other components including excipients, stabilizers, pH adjusting additives (e.g., buffers) and the like. Non-limiting examples of these additives include sodium chloride, citric acid and L-arginine. For example, the use of sodium chloride results in greater stability; L-arginine is used to adjust pH of the aqueous solution (e.g., to pH 5-7) and to increase the solubility of ceftolozane; and citric acid is used to prevent discoloration of the product, due to its ability to chelate metal ions. Preferably, the first aqueous solution comprises about 125 mg-500 mg sodium chloride per 1,000 mg of ceftolozane active. The ceftolozane can be included as an amount of ceftolozane sulfate of formula (I) containing at least about 1,000 mg ceftolozane active.

The products include a tazobactam composition prepared and handled in the absence of ceftolozane by forming a second solution comprising tazobactam acid. The tazobactam can be included in an amount providing about 500 mg of tazobactam acid per 1,000 mg ceftolozane active (i.e., a 1:2 weight ratio of tazobactam acid to ceftolozane active). Tazobactam is a β-lactamase inhibitor of the structure of formula (II) in its free acid form.

Unless otherwise indicated, tazobactam can be a free acid, a sodium salt, an arginine salt, or a hydrate or solvate thereof.

“Split-Fill” Product Presentation

A first presentation of a ceftolozane-tazobactam antibiotic product is a single unit dosage form container that includes the ceftolozane composition and the tazobactam composition (as described above) first combined (blended) within a unit dosage form container. The single unit dosage form container can be obtained by a “split-fill” process comprising the steps of: (a) sequential, aseptic filling of a ceftolozane composition and a tazobactam composition into a unit dosage form container; (b) blanketing the unit dosage form container with an inert gas; and (c) sealing the unit dosage form container, where the ceftolozane composition is prepared and handled in the absence of tazobactam prior to filling into the unit dosage form container, and the tazobactam composition is prepared and handled in the absence of ceftolozane prior to filling into the unit dosage form container. The unit dosage form container can have any suitable configuration or presentation, including a vial or bag, which is sealed to isolate the product from air outside the container. Preferably, the unit dosage form container includes a means for injecting a liquid (e.g., a self-sealing rubber surface on a cap) into the container, such as saline or water for injection, to reconstitute the product as a solution. The ceftolozane composition is preferably obtained in the absence of tazobactam by a process comprising the step of lyophilizing a solution comprising ceftolozane (e.g., as ceftolozane sulfate) and 125 mg-500 mg sodium chloride per 1,000 mg ceftolozane active. The solution can be an aqueous solution that also includes an alkalizing agent (e.g., L-arginine) and/or a chelating agent (e.g., citric acid). The tazobactam composition is preferably obtained in the absence of ceftolozane by a process comprising the step of lyophilizing a solution comprising tazobactam (e.g., as tazobactam acid) and an alkalizing agent such as sodium bicarbonate or sodium hydroxide. The solution can be an aqueous solution. Alternatively, the tazobactam composition can be a crystalline form of tazobactam such as tazobactam sodium or tazobactam arginine crystal solid forms, not prepared by lyophilization. The ceftolozane composition and the tazobactam composition are first combined within a unit dosage form container, preferably in a weight ratio of 2:1 between the equivalent amounts of ceftolozane active and the amount of tazobactam free acid. Unit dosage forms for the treatment of certain infections (e.g., complicated urinary tract infections and/or complicated intra-abdominal infections) can comprise a total of 1,000 mg of ceftolozane active and a total of 500 mg of tazobactam active. Unit dosage forms for the treatment of other infections (e.g., pneumonia infections) can comprise a total of 2,000 mg of ceftolozane active and a total of 1,000 mg of tazobactam active.

Alternatively, pharmaceutical compositions comprising ceftolozane and tazobactam can be obtained by first combining ceftolozane and tazobactam within a unit dosage form container in a liquid solution, then lyophilizing the solution within the unit dosage form container (“co-lyophilized compositions”). The unit dosage form containers obtained by co-lyophilization within a unit dosage form container can include (e.g., up to about 1%) an additional substance having an HPLC retention time of about 1.22 relative to that of ceftolozane (see, e.g., FIG. 6A data showing the presence RRT 1.22 compound at 25 degrees C.). Pharmaceutical compositions comprising ceftolozane and tazobactam prepared by either blending or co-filling processes (e.g., as described in Example 5) have a different composition compared to compositions prepared by co-lyophilization (e.g., as described in Example 3). In contrast, ceftolozane and tazobactam individually lyophilized prior to blending, led to a pharmaceutical composition comprising a much lower amount of the compound of formula (III):

The compound of formula (III) has a relative retention time (RRT) of 1.22 (relative to ceftolozane using the HPLC analysis). This compound is also referred to herein as “the compound RRT 1.22.” Without being bound by theory, the compound RRT 1.22 can be formed by a reaction between ceftolozane and formylacetic acid, a by-product of tazobactam as illustrated in Marunaka et al. (Chem. Pharm. Bull. 1988, Vol. 36 (11), pp. 4478-4487.

The lyophilization of a composition within the unit dosage form container is based in part on the discovery that compositions having lower initial amounts of total Related Substances were obtained by lyophilizing a solution comprising ceftolozane and tazobactam. FIG. 4A is a schematic showing a process for making the compound of formula (III) with ceftolozane and tazobactam. The co-lyophilized compositions can be obtained by a process comprising the steps of: (a) forming a solution (e.g., and aqueous solution) comprising ceftolozane (e.g., ceftolzoane sulfate), and tazobactam (e.g., tazobactam acid), and (b) lyophilizing the solution to obtain the Co-Lyophilized Compositions. Preferably, the solution prior to lyophilization comprises ceftolozane, tazobactam, and about 125-500 mg of sodium chloride per 1,000 mg of ceftolozane active. More preferably, the solution further comprises L-arginine and/or citric acid. Most preferably, the solution comprises ceftolozane and tazobactam in a weight ratio of about 2:1 between the amount of ceftolozane active and the amount of tazobactam acid in the solution prior to lyophilization. The solution can have a pH of about 5-7 (e.g., by including an amount of L-arginine to provide the pH of 5-7, e.g., 6-7). The solution can further comprise sodium bicarbonate and/or other excipients. Examples of aqueous solutions suitable for lyophilization to obtain Co-Lyophilized compositions are provided in the tables in FIG. 4B and FIG. 5. The lyophilization cycle can be performed by any suitable method effective to remove the water or other solvent in the solution. For example, the lyophilization can be performed according to the program in FIG. 2.

Referring to the data tables in FIGS. 6A and 6B, the amount of related substances in co-lyophilized compositions were determined by HPLC as described in Example 2, in two different stability tests. The data in the table of FIG. 6A was obtained from a 3 month stability study where the co-lyophilized composition of FIG. 5 was maintained at 25 degrees C. and 60% relative humidity (RH) for 1 and 3 months. The total amount of related substances in the sample rose from an initial amount of about 1.46% to about 1.98% after 3 months (i.e., about a 36% increase). The data in the table of FIG. 6B was obtained from a 3 month stability study where the co-lyophilized composition of FIG. 5 was maintained at 40 degrees C. and 60% relative humidity (RH) for 1 and 3 months. The total amount of Related Substances in the sample rose from an initial amount of about 1.46% to about 3.85% after 3 months (i.e., about a 264% increase).

Two-Container Product Presentation

A two-container product presentation can be obtained by separately packaging ceftolozane in the absence of tazobactam, and tazobactam in the absence of ceftolozane. The second product presentation comprises separate unit dosage form containers obtained by a “two-container” process comprising the steps of: (a) aseptic filling and sealing of a ceftolozane composition in a first unit dosage form into a first container in the absence of tazobactam; (b) aseptic filling and sealing of a tazobactam composition in a first unit dosage form into a second container in the absence of ceftolozane; and (c) packaging the first container and the second container as a single product for later combination in a fixed dose combination of the ceftolozane composition and the tazobactam composition in a weight ratio of 2:1 between the amount of ceftolozane active and tazobactam free acid. These steps can be performed in any order. The two-container product presentation can also be obtained by a process comprising the steps (performed in any order) including: (a) providing a ceftolozane composition prepared in the absence of tazobactam, (b) providing a tazobactam composition prepared in the absence of ceftolozane, (c) aseptic filling and sealing of the ceftolozane composition in a first unit dosage form into a first container; (d) aseptic filling and sealing of the tazobactam composition in a second unit dosage form into a second container in the absence of ceftolozane; and (c) packaging the first container and the second container as a single product for later combination in a fixed dose combination of the ceftolozane composition and the tazobactam composition in a weight ratio of 2:1 between the amount of ceftolozane active and tazobactam free acid.

In the two-container product presentation, the blended composition is formed by first contacting ceftolozane and tazobactam after opening the containers (e.g., at a location for treating a patient, such as a hospital pharmacy). The two-container product presentation includes a first sealed container comprising ceftolozane obtained and provided in the absence of tazobactam and a second sealed container comprising tazobactam comprising tazobactam obtained and provided in the absence of ceftolozane. The first container and the second container can be opened and the ceftolozane and tazobactam compositions can be combined in a fixed weight ratio corresponding to a 2:1 weight ratio between the amount of ceftolozane active and the amount of tazobactam free acid in the first and second compositions, respectively. The resulting blended composition comprising ceftolozane and tazobactam can be reconstituted in a pharmaceutically acceptable liquid (e.g., physiological saline, or water for injection) for intravenous administration to a patient in need thereof.

The two-container unit dosage form can be obtained by a process comprising the steps of: (a) aseptic filling of a ceftolozane composition into a first container; (b) blanketing the first container with an inert gas; (c) sealing the first container, where the ceftolozane composition is prepared and handled in the absence of tazobactam prior to filling into the first container; (d) aseptic filling of a tazobactam composition into a second container; (e) blanketing the second container with an inert gas; (f) sealing the second container, where the tazobactam composition is prepared and handled in the absence of ceftolozane prior to filling into the unit dosage form container; and (g) packaging the first container and the second container together in a unit dosage form package with instructions for combining the ceftolozane composition and the tazobactam composition in a fixed dose combination prior to administration to a patient.

The containers and packages can have any suitable configuration or presentation, including a vial or bag, which is sealed to isolate the ceftolozane composition and the tazobactam composition both from each other and from air outside the containers. The ceftolozane composition and the tazobactam composition can be combined after opening each respective container either in powder or liquid form in a fixed dose ratio. Preferably, each container includes a means for injecting a liquid (e.g., a self-sealing rubber surface on a cap) into the container, such as saline or water for injection, to reconstitute the product as a solution. The ceftolozane composition in a first container is preferably obtained in the absence of tazobactam by a process comprising the step of lyophilizing a solution comprising ceftolozane (e.g., as ceftolozane sulfate) and 125 mg-500 mg sodium chloride per 1,000 mg ceftolozane active. The solution can be an aqueous solution that also includes an alkalizing agent (e.g., L-arginine) and/or a chelating agent (e.g., citric acid). The tazobactam composition in the second container is preferably obtained in the absence of ceftolozane by a process comprising the step of lyophilizing a solution comprising tazobactam (e.g., as tazobactam acid) and an alkalizing agent such as sodium bicarbonate or sodium hydroxide. The solution can be an aqueous solution. Alternatively, the tazobactam composition in the second container can be a crystalline form of tazobactam such as tazobactam sodium or tazobactam arginine crystal solid forms, not prepared by lyophilization.

The ceftolozane composition and the tazobactam composition are first combined after packaging of the two-container unit dosage form, preferably in a weight ratio of 2:1 between the equivalent amounts of ceftolozane active and the amount of tazobactam free acid. Unit dosage forms for the treatment of certain infections (e.g., complicated urinary tract infections and/or complicated intra-abdominal infections) can comprise a total of 1,000 mg of ceftolozane active and a total of 500 mg of tazobactam active (obtained from at least two containers). Unit dosage forms for the treatment of other infections (e.g., pneumonia infections) can comprise a total of 2,000 mg of ceftolozane active and a total of 1,00 mg of tazobactam active (obtained from at least two containers).

Additional Pharmaceutical Compositions and Methods of Treatment

Pharmaceutical compositions in one or more unit dosage forms can be co-lyophilized compositions and/or blended compositions comprising ceftolozane and tazobactam and can be formulated to treat infections by parenteral administration (including subcutaneous, intramuscular, and intravenous) administration.

Pharmaceutical compositions may additionally comprise excipients, stabilizers, pH adjusting additives (e.g., buffers) and the like. Non-limiting examples of these additives include sodium chloride, citric acid and L-arginine. For example, the use of sodium chloride results in greater stability; L-arginine is used to adjust pH and to increase the solubility of ceftolozane; and citric acid is used to prevent discoloration of the product, due to its ability to chelate metal ions. In one particular embodiment, the pharmaceutical compositions described herein are formulated for administration by intravenous injection or infusion.

The amount of the compound of formula (III) can be increased in the composition as disclosed herein (e.g., by heating a sample produced by co-lyophlization of tazobactam and ceftolozane in an aqueous solution, followed by heating of the lyophilized product to increase the amount of the compound of formula (III)). The compound of formula (III) can also be isolated from compositions comprising ceftolozane and tazobactam and then re-combined with ceftolozane and/or tazobactam to form compositions with desired concentrations of the compound of formula (III). Pharmaceutical compositions can include less than 0.03%, 0.05%, 0.13%, 0.15%, 0.30%, 0.38%, 0.74% or 0.97% of the compound of formula (III), as measured by HPLC. Other pharmaceutical compositions can include a range from less than about 0.03% (e.g., see minimum detected amounts in Tables 4-5) to about 1.0% (e.g., maximum detected amount of RRT 1.22 in Tables 4-5) or more of the compound of formula (III) including compositions comprising 0.03%-0.05%, 0.05%, 0.05%-0.13%, 0.05%-0.15%, 0.03%-0.13%, 0.05%- of the compound of formula (III), where the % of the compound of formula (III) as measured by HPLC using a Develosil column ODS-UG-5; 5 micrometers; 250×4.6 mm, a mobile phase of sodium perchlorate buffer solution (pH 2.5)/CH₃CN 90:10 (v/v) at a 1.0 mL/min flow rate and oven temperature of 45° C. The pharmaceutical antibiotic compositions can include ceftolozane or a pharmaceutically acceptable salt thereof and an amount of the compound of formula (III). Compositions can also be made comprising the compound of formula (III) in the absence of tazobactam and/or in the absence of ceftolozane.

In one example, a pharmaceutical composition in a unit dosage form container comprises ceftolozane sulfate and tazobactam in a ratio of 1,000 mg ceftolozane active per 500 mg of tazobactam active and up to about 1%, more preferably up to about 0.03%-0.05%, of a compound of formula (III) as measured by HPLC using a Develosil column ODS-UG-5; 5 micrometers; 250×4.6 mm, a mobile phase of sodium perchlorate buffer solution (pH 2.5)/CH₃CN 90:10 (v/v) at a 1.0 mL/min flow rate and oven temperature of 45° C. The pharmaceutical composition obtained by a process comprising the steps of lyophilizing an aqueous solution comprising ceftolozane sulfate, tazobactam (e.g., tazobactam free acid and/or tazobactam sodium), 125 mg to 500 mg of sodium chloride per 1,000 mg of ceftolozane active, L-arginine and/or citric acid in an amount effective to adjust the pH of the first aqueous solution to 5-7 (e.g., 6-7) prior to lyophilization to obtain a first lyophilized ceftolozane composition.

Alternatively, the pharmaceutical composition comprising up to about 1% of a compound of formula (III) as measured by HPLC (e.g., with HPLC using a Develosil column ODS-UG-5; 5 micrometers; 250×4.6 mm, a mobile phase of sodium perchlorate buffer solution (pH 2.5)/CH₃CN 90:10 (v/v) at a 1.0 mL/min flow rate and oven temperature of 45° C.) can be obtained by a process comprising the steps of: (a) lyophilizing a first aqueous solution in the absence of tazobactam, the first aqueous solution comprising ceftolozane sulfate, 125 mg to 500 mg of sodium chloride per 1,000 mg of ceftolozane active, L-arginine and/or citric acid in an amount effective to adjust the pH of the first aqueous solution to 5-7 (e.g, 6-7) prior to lyophilization to obtain a first lyophilized ceftolozane composition; (b) lyophilizing a second solution in the absence of ceftolozane, the second solution comprising tazobactam being lyophilized to form a second lyophilized tazobactam composition; and (c) blending within a unit dosage form container the first lyophilized ceftolozane composition, the second lyophilized tazobactam composition and a composition comprising the compound of formula (III).

The pharmaceutical antibiotic compositions can be provided in a unit dosage form container (e.g., in a vial or bag). The unit dosage form can be dissolved with a pharmaceutically acceptable carrier, and then intravenously administered. A unit dosage form of a pharmaceutical composition can be formulated for parenteral administration for the treatment of complicated intra-abdominal infections or complicated urinary tract infections can enclose a pharmaceutical composition comprising the compound of formula (III). Compositions can be produced by co-lyophilization or blending in a vial (e.g., Example 1). For example, an aqueous solution comprising ceftolozane and tazobactam in a vial can be lyophilized to obtain a unit dosage form.

In one aspect, provided herein is a method for the treatment of bacterial infections in a mammal, comprising administering to said mammal a therapeutically effective amount of a pharmaceutical composition prepared according to the methods described herein. A method for the treatment of bacterial infections in a mammal can comprise administering to said mammal a therapeutically effective amount of a pharmaceutical composition comprising ceftolozane sulfate and sodium chloride. Non-limiting examples of bacterial infections that can be treated by the methods of the invention include infections caused by: aerobic and facultative gram-positive microorganisms (e.g., Staphylococcus aureus, Enterococcus faecalis, Staphylococcus epidermidis, Streptococcus agalactiae, Streptococcus pneumonia, Streptococcus pyogenes, Viridans group streptococci), aerobic and facultative gram-negative microorganisms (e.g., Acinetobacter baumanii, Escherichia coli, Haemophilus influenza, Klebsiella pneumonia, Pseudomonas aeruginosa, Citrobacter koseri, Moraxella catarrhalis, Morganella morganii, Neisseria gonorrhoeae, Proteus mirabilis, Proteus vulgaris, Serratia marcescens, Providencia stuartii, Providencia rettgeri, Salmonella enterica), gram-positive anaerobes (Clostridium perfringens), and gram-negative anaerobes (e.g., Bacteroides fragilis group (e.g., B. fragilis, B. ovatus, B. thetaiotaomicron, and B. vulgates), Bacteroides distasonis, Prevotella melaninogenica). In certain embodiments of the methods described herein, bacterial infection is associated with one or more of the following conditions: complicated intra-abdominal infections, complicated urinary tract infections (cUTIs) and pneumonia (e.g., community-acquired, or nosocomial pneumonia). Community-acquired pneumonia (moderate severity only) can include infections caused by piperacillin-resistant, beta-lactamase producing strains of Haemophilus influenza. Nosocomial pneumonia (moderate to severe) caused by piperacillin-resistant, beta-lactamase producing strains of Staphylococcus aureus and by Acinetobacter baumanii, Haemophilus influenzae, Klebsiella pneumoniae, and Pseudomonas aeruginosa.

As used herein, “treating,” “treat,” or “treatment” describes the management and care of a patient for the purpose of combating a disease, condition, or disorder and includes the administration of a pharmaceutical composition of the present invention to alleviate the symptoms or complications of a disease, condition or disorder, or to reduce the extent of the disease, condition or disorder. The term “treat” can also include treatment of a cell in vitro or an animal model.

By a “therapeutically effective amount” of a compound of the invention is meant a sufficient amount of the compound to treat the disorder (e.g., bacterial infection). The specific therapeutically effective amount that is required for the treatment of any particular patient or organism (e.g., a mammal) will depend upon a variety of factors including the disorder being treated and the severity of the disorder; the activity of the specific compound or composition employed; the specific composition employed; the age, body weight, general health, sex and diet of the patient; the time of administration, route of administration, and rate of excretion of the specific compound employed; the duration of the treatment; drugs used in combination or coincidental with the specific compound employed; and like factors well known in the medical arts (see, for example, Goodman and Gilman's, “The Pharmacological Basis of Therapeutics”, Tenth Edition, A. Gilman, J. Hardman and L. Limbird, eds., McGraw-Hill Press, 155-173, 2001, which is incorporated herein by reference in its entirety). The therapeutically effective amount for a given situation can be readily determined by routine experimentation and is within the skill and judgment of the ordinary clinician.

As used herein, “1000 mg ceftolozane” refers to an amount of ceftolozane that is considered a bioequivalent by the United States Food and Drug Administration (FDA), i.e. for which 90% CI of the relative mean Cmax, AUC(0-t) and AUC(0-∝) is within 80.00% to 125.00% of the reference formulation in the fasting state (see: “Guidance for Industry: Bioavailability and Bioequivalence Studies for Orally Administered Drug Products—General Considerations”. Center for Drug Evaluation and Research, United States Food and Drug Administration, 2003).

As used herein, the term “ceftolozane active” refers to active portion of a salt form of ceftolozane, the free base form of ceftolozane.

As used herein, the term “tazobactam active” refers to the active portion of a salt form of tazobactam, tazobactam free acid form.

As used herein, “1,000 mg of ceftolozane as ceftolozane active” refers to an amount of ceftolozane sulfate effective to provide 1,000 mg of ceftolozane. The amount of sodium per gram of ceftolozane activity in a pharmaceutical composition containing ceftolozane sulfate and sodium chloride can be calculated using the relevant molecular weights of ceftolozane, ceftolozane sulfate, sodium chloride and sodium.

ILLUSTRATIVE EXAMPLES OF SELECTED EMBODIMENTS OF THE INVENTION Example 1 Manufacturing Procedure of Bulk (Tray) Lyophilized Ceftolozane

There are four main steps in the manufacture of CXA-101 bulk drug product: dissolution, sterile filtration, bulk lyophilization, and packaging into Sterbags®. These four main steps are composed of a total of 20 minor steps. The CXA-101 bulk drug product manufacturing process is presented below.

I. Dissolution

1. The prescribed amount of water for injection (“WFI”) is charged into the dissolution reactor.

2. A prescribed amount of citric acid is added.

3. The solution is cooled at 5° C. to 10° C.

4. A prescribed amount of CXA-101 drug substance is added to the solution.

5. A prescribed amount of L-arginine is slowly added to the solution.

6. A check for complete dissolution is performed. Solution pH is verified to be in the target range of 6.5 to 7.0.

7. A prescribed amount of sodium chloride is added to the solution.

8. A check for complete dissolution is performed. Solution pH is verified to be in the target range of 6.0 to 7.0. If the pH is out of this range adjust with either L-Arginine or citric acid.

9. WFI is added to bring the net weight to 124.4 kg and the solution is mixed well.

10. Samples are withdrawn for testing of final pH.

II. Sterile Filtration

11. The solution is passed through the filter (pore size 0.45 μm) followed by double filters (pore size 0.22 μm) onto a shelf on the Criofarma lyophilizer.

12. The line is washed with WFI.

13. The washing solution is passed from Step 12 through sterile filtration.

III. Bulk Lyophilization

14. The washing solution is loaded onto a separate shelf in the lyophilizer (and later discarded).

15. The solution is lyophilized until dry.

16. The product shelf is cooled to 20° C.±5° C.

IV. Packaging into Sterbags®

17. The lyophilized bulk drug product powder is milled.

18. The milled powder is sieved.

19. The sieved powder is blended for 30 minutes.

20. The powder is then discharged into Sterbags®

Prefiltration and Sterile-Filtration

Filtrate the compounded solution with a sterile tilter-set which consists of a 0.2 um polyvinylidene fluoride membrane filter (Durapore®, Millipore) and a 0.1 urn polyvinylidene fluoride membrane filter (Durapore®, Millipore) connected in tandem. Confirm the integrity of each filter before and after the filtration. Take approximately 100 mL of the filtrate in order to check bioburden.

Filter the prefiltered compounded solution through a sterile filter-set which consists of a 0.2 um polyvinylidene fluoride membrane filter and a 0.1 urn polyvinylidene fluoride membrane filter connected in tandem, and introduce the final filtrate into an aseptic room. Confirm the integrity of each filter before and after the filtration.

Processing of Vial, Stopper and Flip-Off Cap

Wash a sufficient quantity of 28 mL vials with water for injection and sterilize the washed vials by a dry-heat sterilizer. Then transfer the sterilized vials into a Grade A area located in an aseptic room.

Wash a sufficient quantity of stoppers with, water for injection. Sterilize and dry the washed stoppers by steam sterilizer. Then transfer the sterilized stoppers into a Grade A area located in an aseptic room.

Sterilize a sufficient quantity of flip-off caps by steam sterilizer. Then transfer the sterilized flip-off caps into a Grade A or B area located in an aseptic room.

Filling and Partially Stoppering

Adjust the fill weight of the filtered compounded solution to 11.37 g (corresponds to 10 mL of the compounded solution), then start filling operation. Check the filled weight in sufficient frequency and confirm it is in target range (11.37 g±1%, 11.26 to 11.43 g). When deviation from the control range (11.37 g±2%, 11.14 to 11.59 g) is occurred, re-adjust the filling weight.

Immediately after a vial is filled, partially stopper the vial with a sterilized stopper. Load the filled and partially stoppered vials onto the shelves of a lyophilizer aseptically.

Lyophilization to Crimping, Visual Inspection, Labeling and Packaging

After all filled and partially stoppered vials are loaded into a lyophilizer, start the lyophilization program shown in FIG. 2. Freeze the loaded vials at −40° C. and keep until all vials freeze. Forward the program to primary drying step (shelf temperature; −20° C., chamber pressure; 100 to 150 mTorr). Primary drying time should be determined by monitoring the product temperature. Forward the program to secondary drying step (shelf temperature; 30° C., chamber pressure; not more than 10 mTorr) after completion of the primary drying step. After all vials are dried completely, return the chamber pressure to atmospheric pressure with sterilized nitrogen. Then stopper vials completely.

Unload the lyophilized vials from the chamber and crimp with sterilized flip-off caps.

Subject all crimped vials to visual inspection and label and package all passed vials.

Example 2 Analytical HPLC Method

A. Operative Conditions

Column Develosil ODS-UG-5; 5 μm, 250 × 4.6 mm (Nomura Chemical, Japan) Mobile phase Sodium Perchlorate Buffer Solution (PH 2.5)/ CH₃CN 90:10 (vlv) Flow rate 1.0 mL/min Wavelength 254 nm Injection volume 10 μL Oven 45° C. Temperature Run Time 85 minutes Time (min) A % B % Gradient Profile: 0 75 25 30 70 30 60 0 100 85 0 100 85.1 75 25 110 75 25 B. Mobile Phase Preparation.

Sodium Perchlorate Buffer Solution was made by dissolving 14.05 g of sodium perchlorate Monohydrate in 1000.0 mL of water followed by adjusting pH to 2.5 with diluted perchloric acid (1 in 20).

Mobile Phase was then made by mixing Sodium Perchlorate Buffer Solution (pH 2.5) and acetonitrile in the ratio 90:10 (v/v).

Sodium Acetate Buffer Solution pH 5.5 (Diluent) was made by dissolving 1.36 g of sodium acetate trihydrate in 1000.0 mL of water followed by adjusting to pH 5.5 with diluted acetic acid (1 in 10).

C. Sample Preparation.

Sample solution: dissolve 20.0 mg, exactly weighed, of Sample, in 20.0 mL of water (Prepare just before injection into HPLC system).

System Suitability Solution (1%): take 1.0 mL of the Sample Solution (use first sample if more are present) and transfer into a 100.0 mL volumetric flask, dilute with water to volume and mix.

D. HPLC Analysis Procedure

-   1. Inject Blank (water) -   2. Inject System Suitability Solution and check for tailing factor     and theoretical plate number for CXA-101 peak:

The tailing factor must not be greater than 1.5

Theoretical plates number must not be less than 10000

-   3. Inject Sample Solution -   4. Inject System Suitability Solution and check for tailing factor     and theoretical plate number for CXA-101 peak.

The tailing factor must not be greater than 1.5

Theoretical plates number must not be less than 10000

-   5. Identify the peaks of related substances in the sample     chromatogram based on the reference chromatogram reported in FIGS.     1A and 1B or, alternatively, on the basis of the RRT values reported     in Table 1 (FIG. 3). The material for “Peak 1” in the Table 1 of     FIG. 3, with a retention time of about 0.14 relative to ceftolozane     is believed to have the chemical structure of formula (II):

E. Calculations

-   I. Report for each related substance is amount as expressed by area     percent.

$C_{i} = \frac{A_{i} \times 100}{A_{t} + {\Sigma\; A_{i}}}$

wherein:

C_(i)=Amount of related substance i in the Sample, area %

A_(i)=Peak area of related substance i in the Sample chromatogram

A_(t)=Area of CXA-101 peak in the Sample chromatogram

A_(t)+ΣA_(i)=Total peaks area in the Sample chromatogram

Consider as any Unspecified Impurity, each peak in the chromatogram except CXA-101, peaks from 1 to 11 and every peak present in the blank chromatogram and report the largest.

-   II. Report the total impurities content as expressed by the     following formula:

$C_{T} = \frac{A_{i} \times 100}{A_{t} + {\Sigma\; A_{i}}}$

wherein:

C_(T)=total impurities content in the Sample, area %

A_(t)=area of CXA-101 peak in the sample chromatogram

ΣA_(i)=total peak areas of impurities in the sample chromatogram

Example 3 Manufacturing Combination Product (Tazobactam and Ceftolozane) by Co-Lyophilization

Compositions comprising the compound of formula (III) were prepared by the process shown in FIG. 4A by (a) forming an aqueous solution comprising the components in Table 3 (FIG. 5), and (b) lyophilizing the aqueous solution. Sodium content was approximately 78 mg/g of tazobactam in drug product after lyophilization. Water was removed during the lyophilization process and is controlled at no more than 4% by weight.

Example 4 Assessment of Blend Combination Drug Product

A. Preparation of Blend Combination Drug Product

The blend drug product was prepared, as described above in Example 3, on lab scale by use of a small blender. The composition of the blend drug product is shown in Table 3, FIG. 5. The CXA-101 was obtained by lyophilization of ceftolozane sulfate in the absence of tazobactam, and the tazobactam sodium material was obtained by lyophilization of tazobactam prior to blending of the ceftolozane and tazobactam components.

B. Stability Test

The sample prepared herein (Example 4A) was put into a stability study. Tables 4 (FIG. 6A) and 5 (FIG. 6B) are representative examples that summarize the results at 25° C./RH=60% and 40° C./RH=75% after one month (T1) and three months (T2). Samples were analyzed using a HPLC method as described in Example 1.

C. Conclusion

The data at both 25° C. and at 40° C. have shown that the blending process inhibits formation of amounts of the impurity RRT=1.22 to below the detection limit of the HPLC method of Example 2.

Example 5 Manufacturing of Combination Product (Tazobactam and CXA-101) by Blending Sterile Dry Blending of Bulk Lyophilized Ceftolozane and Bulk Lyophilized Tazobactam

The CXA-101 produced by Example 1 is blended with lyophilized tazobactam. A low energy drum blender that agitates the material by tumbling and also moving the bed up and down is used. For CXA-101/tazobactam for injection, the blender was charged with 23.4 kg of CXA-101 bulk product, and 5.4 kg of tazobactam bulk product. Both the CXA-101 and tazobactam were individually lyophilized beforehand. The material was blended for 180 minutes. In-process tests of content assay for both CXA-101 and tazobactam were performed to assess the homogeneity using the samples of blend materials taken from three places. The RSD for each of CXA-101 and tazobactam content assay was no greater than 2% and the RSD for the ratio of CXA-101/tazobactam was no greater than 2.2%. (See Table 6 in FIG. 7).

The blended powder is then discharged into Sterbags®.

Example 6 Co-Lyophilization of Ceftolozane and Tazobactam Produces the Compound of Formula (III) (RRT 1.22)

The co-lyophilized combo drug product was prepared as described above in Example 3. The formulation composition of the co-lyophilized combo drug product is shown in FIG. 8 (Table 7). This sample was maintained at 25° C./RH=60% and 40° C./RH=75% after one month (T1) and three months (T2). Samples were analyzed using a HPLC method as described in Example 2. The data for analysis of the samples by HPLC is shown in the tables in FIG. 9A (Table 4: Stability data of Co-Lyo Combo Drug Product at 25° C.) and FIG. 9B (Table 5: Stability data Co-Lyo Combo Drug Product at 40° C.). The presence of the compound of Formula (III) was identified has having a retention time of about 1.22 as measured by HPLC (see Example 2). RRT=1.22 was observed in co-lyophilized drug product. The compound of formula (III) is believed to be formed by a reaction between ceftolozane and formylacetic acid, which was a degradation product of tazobactam. The amount of the compound of formula (III) in a composition comprising ceftolozane and tazobactam can be increased over time at 25° C. and at 40° C.

A new impurity having RRT=1.22 was observed in co-lyophilized drug product. The impurity was identified as a degradation product of formula (III) which was formed by a reaction between ceftolozane and formylacetic acid, which was a degradation product of tazobactam. The stability data at 25° C. and at 40° C. have shown that the impurity increases over time.

Example 7 Assessment of Blend Combination Drug Product

A. Preparation of Blend Combination Drug Product

The blend drug product was prepared, as described above in Example 5, on lab scale by use of a small blender. The composition of the blend drug product is shown in Table 7. The CXA-101 was obtained by lyophilization of ceftolozane sulfate in the absence of tazobactam, and the tazobactam sodium material was obtained by lyophilization of tazobactam prior to blending of the ceftolozane and tazobactam components.

B. StabilityTest

The sample prepared herein (Example 7A) was put into stability study. The following Tables 8 and 9 (FIGS. 9A and 9B) are representative examples that summarize the results at 25° C./RH=60% and 40° C./RH=75% after one month (T1) and three months (T2). Samples were analyzed using a HPLC method as described in Example 2.

C. Conclusion

The data at both 25° C. and at 40° C. have shown that the blending process completely inhibits formation of the impurity RRT=1.22.

Example 8 Screening of Stabilizing Agents

A stability study of Combo Drug Product for Injection bulk drug product was carried out at long term storage conditions (e.g., 25° C./60% RH), in accordance with ICH guidelines. This formal stability study examined the effect of temperature and humidity on CXA-101/tazobactam for Injection bulk drug product stability when stored in the container closure configuration of Sterbag®.

A stability study of Combo Drug Product for Injection finished drug product was carried out at long term storage conditions (e.g., 25° C., 60% RH), and an accelerated stability condition (e.g., 40° C./75% RH), in accordance with ICH guidelines. This formal stability study examined the effect of temperature and humidity on CXA-101/tazobactam product stability in the container closure configuration of the finish product vial.

Example 9 Preferred Pharmaceutical Composition Comprising Ceftolozane and Tazobactam

Pharmaceutical compositions comprising ceftolozane and tazobactam with less than 0.15% (measured by HPLC according to Example 2) of the compound of formula (III) can be obtained as described herein.

TABLE 10 Excipients Used in Ceftolozane Composition Inactive Concentration Ingredients Amount, in Infusion Rationale for Database Component Function mg/Vial Solution, % Inclusion (IID) Range Citric acid Chelating  21 0.02 Used to prevent 0.0025 to 50% agent discoloration and degradation Sodium Stabilizing 487 0.49 Used as a stabilizing  0.187 to 45% Chloride agent agent for ceftolozane sulfate L-arginine Alkalizing 600^(i)) 0.60 Used to adjust  0.29 to 88% agent Q.S. for pH ceftolozane solution adjustment pH ^(i))L-arginine is added as needed to achieve pH 6.5 ± 0.5; 600 mg per vial is considered a representative total amount.

TABLE 11 Unit Compositions of Ceftolozane/Tazobactam for Injection, 1000 mg/500 mg Nominal Composition Component Function mg per Vial Ceftolozane Ceftolozane Active 1147  composition¹⁾ Sulfate Citric Acid, Chelating  21 Anhydrous Agent Sodium Stabilizing 487 Chloride Agent L-Arginine Alkalizing   600²⁾ Agent Q.S. for pH adjustment Tazobactam Sodium³⁾ Active 537 Nitrogen Processing Q.S. Aid^(ii)) Total Weight 2792  ¹⁾Actual amount of ceftolozane will vary based on the measured potency. Ceftolozane sulfate, 1147 mg, corresponds to 1000 mg ceftolozane free base. ²⁾L-arginine is added as needed to achieve pH 6.5 ± 0.5; 600 mg per vial is considered a representative total amount. ³⁾Actual weight of tazobactam sodium will vary based on the measured potency. Tazobactam sodium 537 mg, corresponds to 500 mg tazobactam free acid 4) Nitrogen blanket is applied after powders are dispensed to the vial and prior to insertion of stopper.

A first aqueous solution comprising the ingredients in the ceftolozane drug composition in Table 11 is lyophilized in the absence of tazobactam to provide the lyophilized ceftolozane composition. The first aqueous solution comprises ceftolozane sulfate and the specific excipients in the preferred compositions, in an amount per unit dosage form provided by the quantities and functions as provided in Table 10. All excipients are compendial and typical for sterile pharmaceutical dosage forms, requiring no additional treatment prior to use in the formulation. The excipients are used in levels within the range established in other FDA approved products as described in the Inactive Ingredients Database (IID). A second solution comprising tazobactam acid and sodium bicarbonate is lyophilized in the absence of ceftolozane to obtain the tazobactam sodium composition in Table 11. Subsequently, the lyophilized tazobactam sodium composition is dry blended with the lyophilized ceftolozane composition comprising tazobactam sodium and ceftolozane sulfate in a weight ratio providing 500 mg of tazobactam acid equivalent per 1,000 mg of ceftolozane active equivalent. 

The invention claimed is:
 1. A sterile pharmaceutical composition comprising tazobactam, or a pharmaceutically acceptable salt thereof, and ceftolozane, or a pharmaceutically acceptable salt thereof, in a sealed unit dosage form container, wherein the ceftolozane, or a pharmaceutically acceptable salt thereof, and the tazobactam, or a pharmaceutically acceptable salt thereof, provide ceftolozane active and tazobactam active in a ratio of 2:1 by weight, and wherein said ceftolozane, or a pharmaceutically acceptable salt thereof, and the tazobactam, or a pharmaceutically acceptable salt thereof, were not in physical contact prior to filling the composition into said unit dose form container.
 2. The pharmaceutical composition of claim 1, wherein the pharmaceutically acceptable salt of ceftolozane is ceftolozane sulfate.
 3. The pharmaceutical composition of claim 1, wherein the pharmaceutically acceptable salt of tazobactam is tazobactam sodium or tazobactam arginine.
 4. The pharmaceutical composition of claim 3, wherein the pharmaceutically acceptable salt of tazobactam is tazobactam sodium.
 5. The pharmaceutical composition of claim 1, wherein the amount of ceftolozane active is 1,000 mg and the amount of tazobactam active is 500 mg.
 6. The pharmaceutical composition of claim 1, wherein the amount of ceftolozane active is 2,000 mg and the amount of tazobactam active is 1,000 mg.
 7. The pharmaceutical composition of claim 1, wherein the tazobactam, or a pharmaceutically acceptable salt thereof, and the ceftolozane, or a pharmaceutically salt thereof, were individually lyophilized prior to filling.
 8. The pharmaceutical composition of claim 1, wherein the unit dosage form container includes a means for injecting a liquid into the container.
 9. An injectable composition for intravenous administration comprising the pharmaceutical composition of claim 1 dissolved in a pharmaceutically acceptable carrier.
 10. A pharmaceutical composition comprising tazobactam, or a pharmaceutically acceptable salt thereof, and ceftolozane, or a pharmaceutically salt thereof, prepared by aseptically filling the tazobactam, or a pharmaceutically acceptable salt thereof, and the ceftolozane, or a pharmaceutically salt thereof, in a unit dosage form container and then sealing the unit dosage form container, wherein the ceftolozane, or a pharmaceutically acceptable salt thereof, and tazobactam, or a pharmaceutically acceptable salt thereof, provide ceftolozane active and tazobactam active in a ratio of 2:1 by weight.
 11. The pharmaceutical composition of claim 10, wherein the unit dosage form container is blanketed with an inert gas prior to sealing.
 12. The pharmaceutical composition of claim 10, wherein the ceftolozane, or a pharmaceutically acceptable salt, thereof and the tazobactam, or a pharmaceutically acceptable salt thereof, were not in physical contact prior to filling the composition into said unit dose form container.
 13. The pharmaceutical composition of claim 10, wherein the tazobactam, or a pharmaceutically acceptable salt thereof, and the ceftolozane, or a pharmaceutically acceptable salt thereof, are co-filled into the unit dosage form container.
 14. The pharmaceutical composition of claim 10, wherein the pharmaceutically acceptable salt of ceftolozane is ceftolozane sulfate.
 15. The pharmaceutical composition of claim 10, wherein the pharmaceutically acceptable salt of tazobactam is tazobactam sodium or tazobactam arginine.
 16. The pharmaceutical composition of claim 15, wherein the pharmaceutically acceptable salt of tazobactam is tazobactam sodium.
 17. The pharmaceutical composition of claim 10, wherein the amount of ceftolozane active is 1,000 mg and the amount of tazobactam active is 500 mg.
 18. The pharmaceutical composition of claim 10, wherein the amount of ceftolozane active is 2,000 mg and the amount of tazobactam active is 1,000 mg.
 19. The pharmaceutical composition of claim 10, wherein the tazobactam, or a pharmaceutically acceptable salt thereof, and the ceftolozane, or a pharmaceutically acceptable salt thereof, were individually lyophilized prior to filling.
 20. The pharmaceutical composition of claim 10, wherein the unit dosage form container includes a means for injecting a liquid into the container.
 21. An injectable composition for intravenous administration comprising a pharmaceutical composition of claim 10 dissolved in a pharmaceutically acceptable carrier. 